Client Initiated Idle Mode Transition

ABSTRACT

In accordance with some embodiments, a user equipment can initiate connected-to-idle mode transitions. A three way handshake is undertaken before allowing network disconnection. The transition can be made with a reasonable amount of signaling overhead.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Provisional Application Ser. No.61/612,188, filed Mar. 16, 2012, hereby expressly incorporated byreference herein.

BACKGROUND

This relates generally to radio communications and, particularly, tocellular radio communications.

Many radio operated devices have an increasing number of applicationsthat send only a small amount of data. The transmission frequency ofsuch packets is relatively high. “Always on applications” include email,chat, instant messaging, stock updates, and weather updates. Thus,because of the frequency of transmission, power consumption may tend tobe excessive.

There is a mechanism called fast dormancy that allows mobile devices toreduce their power consumption when they come to the decision thatphysical conductivity to the network is no longer required. Fastdormancy has been removed from the 3GPP standards for power savingpurposes.

Embodiments may find application in a wireless local area network (WLAN)or a wireless wide area network (WWAN) including a WiMAX (WorldwideInteroperability for Microwave Access) network or the like. WiMAXtechnology is based on the IEEE 802.16 family of standards, includingIEEE 802.16e, IEEE 802.16m, and others. Embodiments herein may also beapplicable to other WWANs such as those operating according to 3GPP LongTerm Evolution (LTE) or LTE-Advanced, or similar, follow-on wirelessstandards. Further, while several specific standards have been set forthherein as examples of suitable applications, implementations herein arenot limited to any particular standard or protocol.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments are described with respect to the following figures:

FIG. 1 is a schematic depiction of a user equipment according to oneembodiment;

FIG. 2 is a flow chart for one embodiment; and

FIG. 3 is a depiction of medium access control control element for oneembodiment.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawings.The same reference numbers may be used in different drawings to identifythe same or similar elements. In the following description, for purposesof explanation and not limitation, specific details are set forth suchas particular structures, architectures, interfaces, techniques, etc. inorder to provide a thorough understanding of the various aspects of theclaimed invention. However, it will be apparent to those skilled in theart having the benefit of the present disclosure that the variousaspects of the invention claimed may be practiced in other examples thatdepart from these specific details. In certain instances, descriptionsof well-known devices, circuits, and methods are omitted so as not toobscure the description of the present invention with unnecessarydetail.

In accordance with some embodiments, a user equipment can initiateconnected-to-idle mode transitions. A three way or step handshake isundertaken before allowing network disconnection. The transition can bemade with a reasonable amount of signaling overhead.

As shown in FIG. 1, the user equipment 10 may include a radio frequencyantenna 12, coupled to a transceiver 14. The transceiver 14, in turn, iscoupled to a processor 16, which may be an application processor or adigital signal processor. The processor 16 is coupled to a storage 18.The storage 18 may include an uplink buffer 20 and a downlink buffer 22.

In some implementations, the processor 16 can be a single processingunit or a number of processing units, all of which may include multiplecomputing units or multiple cores. The processor 16 may be implementedas one or more microprocessors, microcomputers, microcontrollers,digital signal processors, central processing units, state machines,logic circuitries, and/or any devices that manipulate signals based onoperational instructions. Among other capabilities, the processor 16 canbe configured to fetch and execute processor-executable instructionsstored in the storage 18, respectively, or other processor-readablestorage media.

The storage 18 can include any processor-readable storage media known inthe art including, for example, volatile memory (e.g., RAM) and/ornon-volatile memory (e.g., flash, etc.), mass storage devices, such ashard disk drives, solid state drives, removable media, includingexternal drives, removable drives, floppy disks, optical disks, or thelike, or any combination thereof. The storage 18 may storecomputer-readable processor-executable program instructions as computerprogram code that can be executed by the processor 16 as a particularmachine for carrying out the methods and functions described in theimplementations herein. Further, storage 18 may also include otherprogram modules stored therein and executable by processor 16 forcarrying out implementations herein, such codecs, or the like.

Additionally, transceiver 14 may be implemented in a variety of devicesand systems, such as cellular communications systems, Wi-Fi systems, orthe like. For example, transceiver 14 might be incorporated in a mobilecomputing device, such as a cell phone, smart phone, laptop, wirelessaccess point, a second computing device, or the like, or vice versa.Further, while exemplary system architectures have been described, itwill be appreciated that other implementations are not limited to theparticular system architectures described herein. For example, thetechniques and architectures described herein may be incorporated in anyof a variety of wireless communication devices, and implementationsherein are not limited to any type of communication devices.

In the downstream or downlink case, the user equipment 10 maycommunicate with devices that are interchangeably referred to as a basestation (BS) or evolved or enhanced Node B (eNB) or access point (AP) atthe system level herein. In this downlink case, the transceiver 14 abovemay be interchangeably referred to as a mobile station (MS) or userequipment (UE) or station (STA) at the system level herein. Further, theterms BS, eNB, and AP may be conceptually interchanged, depending onwhich wireless protocol is being used, so a reference to BS herein mayalso be seen as a reference to either of eNB or AP. Similarly, areference to MS herein may also be seen as a reference to either of UEor STA.

When the user equipment transmits the last packet in its uplink buffer20, it tells the evolved or enhanced node B (eNB) that it intends todisconnect from the network. The user equipment may also specify a timelimit. The time limit specifies the first time after which an eNB grant,for network access for transmission or reception, may be received. Thetime limit creates a forced minimum delay for the next grant (FMD-NG).The time limit parameter allows the user equipment to wait anappropriate amount of time before confirming that it should expect nomore packets to its uplink buffer.

The time limit parameter can be different for different applications onthe user equipment. Selection of this parameter can be a clientdifferentiator that allows client vendors to optimize the tradeoffbetween battery power consumption and latency. Also, this time limitshould be less than the eNB dormancy timer (i.e. RRC Inactivity Timer)that forces the user equipment into the idle mode. The dormancy timeforces the user equipment to idle mode after a specified period ofinactivity measured by an absence of transmitted or received packets.

In one embodiment, a medium access control (MAC) control element (CE)may be used to implement this sequence. The medium access controlcontrol element is a faster-transition-to-idle (FTI) medium accesscontrol control element having a header field of the form R/R/E/LCID anda control element of length one octet. A new value for the logicalchannel identifier for uplink shared channel can be assigned for the newFTI medium access control control element. One of the reserved logicalchannel identifiers (LCIDs) for the uplink shared channel may be usedfor this purpose.

A faster-transition-to-idle medium access control control element (FIG.3) may be 8 bits, including a faster-transition-to-idle mode bit,indicating an intention to go to idle mode when the FTI bit is equal toone. When the FTI bit is equal to one, the eNB may ignore the otherbits. An FTI bit equal to zero indicates a user equipment's intention toget the next grant no earlier than the period indicated by a forcedminimum delay for next grant (FMD-NG) bits. There may be three R bitsthat are “reserved” for future use. The FMD-NG bits indicate that theuser equipment wants to get the next uplink grant no earlier than thetime period specified by those bits. In one embodiment, 16 valuespossible with four bits are available that may be mapped to an index 0to 15. For example, 0000 can be a forced minimum time for next grant of20 milliseconds, while 1111 may be 500 milliseconds.

Then, the user equipment receives the grant after the time limit fromthe eNB. Next, the user equipment sends its confirmation ondisconnecting from the network if there is no packet coming into itsuplink buffer, or there is no indication to receive packets in thedownlink buffer. The user equipment can send a confirmation ondisconnecting from the network by using the FTI medium access controlcontrol element with FTI bit set equal to one.

In case there is a packet that has arrived in its uplink buffer, theuser equipment transmits the packet. If this is the last packet in thebuffer, then the disconnection can continue.

If there is any indication of receiving packets in the downlink buffer,the user equipment terminates the disconnection process.

When there is no activity in the uplink or downlink buffers for a periodof time, the user equipment can initiate disconnection using the radioresource control (RRC) signaling based on the medium access controlcontrol element based mechanism as usual. That can be different from thesequence described above for user equipment initiated disconnecting atthe end of an uplink data transmission.

Thus, a three way or step handshake is used, including (1) a request totransition to idle from the user equipment, (2) a granting of therequest by an eNB, and (3) a confirmation by the user equipment.

The idle transition sequence 30, shown in FIG. 2, may be implemented insoftware, firmware and/or hardware. In software and firmwareembodiments, it may be implemented by computer executed instructionsstored in one or more non-transitory computer readable media, such as amagnetic, optical, or semiconductor storage.

The sequence 30 may begin by determining if the last packet has beentransmitted from its uplink buffer, as determined in diamond 32. If not,the sequence waits for the last packet.

If it is the last packet, a disconnect notification is sent, asindicated in block 34. A disconnect notification includes the forcedminimum delay for next grant, as indicated in block 36. Then, at block38, the next grant is received after the expiration of the forcedminimum delay for next grant time limit. If there is no packet in theuplink buffer, as indicated in diamond 40, and there is no indication toreceive packets in the downlink buffer, as indicated in block 44, thenthe disconnection can be confirmed (block 48) using thefaster-transition-to-idle medium access control control element with theFTI bit set to one.

However, if there is a packet in the uplink buffer, it may betransmitted, as indicated in block 42, and the flow returns to block 40to check that no more packets are in the uplink buffer.

If there is an indication to receive packets in the downlink buffer,then the disconnection is terminated, as indicated in block 46, and theflow returns back to diamond 32.

The following clauses and/or examples pertain to further embodiments:

One example embodiment may be a method comprising sending a notificationfrom user equipment of an intent to transition to idle mode, specifyinga forced minimum delay for next grant, receiving a grant, checkingwhether a packet is in uplink or downlink buffers, and if no packets arein the buffers, confirming a transition to idle. The method may alsoinclude using a medium access control control element to specify saidforced minimum delay for next grant. The method may also include using alogical channel identifier for an uplink shared channel in said element.The method may also include using a bit to signal a transition to idle.The method may also include using bits to signal a selectable delaytime. The method may also include if a packet has arrived in the uplinkbuffer, transmitting the packet before transitioning to idle. The methodmay also include if there is an indication to receive packets in thedownlink buffer, discarding the transition to idle. A method may alsoinclude specifying a forced minimum delay for next grant to indicatewhen another grant of network access is requested. A method may alsoinclude specifying a forced minimum delay for next grant that is shorterthan an evolved node B dormancy timer. A method may also includerequesting an immediate transition to idle mode.

In another example embodiment one or more non-transitory computerreadable media storing instructions to cause a processor in a wirelessdevice to perform a sequence comprising sending a notification from userequipment of an intent to transition to idle mode, specifying a forcedminimum delay for next grant, receiving a grant, checking whether apacket is in uplink or downlink buffers, and if no packets are in thebuffers, confirming a transition to idle. The media may further storeinstructions to perform a sequence including using a medium accesscontrol control element to specify said forced minimum delay for nextgrant. The media may further store instructions to perform a sequenceincluding using a logical channel identifier for an uplink sharedchannel in said element. The media may further store instructions toperform a sequence including using a bit to signal a transition to idle.The media may further store instructions to perform a sequence includingusing bits to signal a selectable delay time. The media may furtherstore instructions to perform a sequence including if a packet hasarrived in the uplink buffer, transmitting the packet beforetransitioning to idle. The media may further store instructions toperform a sequence including if there is an indication to receivepackets in the downlink buffer, discarding the transition to idle. Themedia may further store instructions to perform a sequence includingspecifying a forced minimum delay for next grant to indicate whenanother grant of network access is requested. The media may furtherstore instructions to perform a sequence including specifying a forcedminimum delay for next grant that is shorter than an evolved node Bdormancy timer. The media may further store instructions to perform asequence including requesting an immediate transition to idle mode.

Another example embodiment may be an apparatus comprising a transceiverto send a notification of an intent to transition to idle mode and toreceive a grant, and a processor coupled to said transceiver to specifya forced minimum delay for next grant, check for a packet in uplink ordownlink buffers, and if no packets are in the buffers, confirm atransition to idle. The apparatus may include said transceiver to use amedium access control control element to specify said forced minimumdelay for next grant. The apparatus may include said transceiver to usea logical channel identifier for an uplink shared channel in saidelement. The apparatus may include said transceiver to use a bit tosignal a transition to idle. The apparatus may include said transceiverto use bits to signal a selectable delay time. The apparatus may includeif a packet has arrived in the uplink buffer, said transceiver totransmit the packet before transitioning to idle. The apparatus mayinclude if there is an indication to receive packets in the downlinkbuffer, said processor to discard the transition to idle. The apparatusmay include said processor to specify a forced minimum delay for nextgrant to indicate when another grant of network access is requested. Theapparatus may include said processor to specify a forced minimum delayfor next grant that is shorter than an evolved node B dormancy timer.The apparatus may include said processor to request an immediatetransition to idle mode.

References throughout this specification to “one embodiment” or “anembodiment” mean that a particular feature, structure, or characteristicdescribed in connection with the embodiment is included in at least oneimplementation encompassed within the present invention. Thus,appearances of the phrase “one embodiment” or “in an embodiment” are notnecessarily referring to the same embodiment. Furthermore, theparticular features, structures, or characteristics may be instituted inother suitable forms other than the particular embodiment illustratedand all such forms may be encompassed within the claims of the presentapplication.

While the present invention has been described with respect to a limitednumber of embodiments, those skilled in the art will appreciate numerousmodifications and variations therefrom. It is intended that the appendedclaims cover all such modifications and variations as fall within thetrue spirit and scope of this present invention.

What is claimed is:
 1. A method comprising: sending a notification fromuser equipment of an intent to transition to idle mode; specifying aforced minimum delay for next grant; receiving a grant; checking whethera packet is in uplink or downlink buffers; and if no packets are in thebuffers, confirming a transition to idle.
 2. The method of claim 1including using a medium access control control element to specify saidforced minimum delay for next grant.
 3. The method of claim 1 includingusing a logical channel identifier for an uplink shared channel in saidelement.
 4. The method of claim 3 including using a bit to signal atransition to idle.
 5. The method of claim 3 including using bits tosignal a selectable delay time.
 6. The method of claim 1 including if apacket has arrived in the uplink buffer, transmitting the packet beforetransitioning to idle.
 7. The method of claim 6 including, if there isan indication to receive packets in the downlink buffer, discarding thetransition to idle.
 8. The method of claim 1 including specifying aforced minimum delay for next grant to indicate when another grant ofnetwork access is requested.
 9. The method of claim 1 includingspecifying a forced minimum delay for next grant that is shorter than anevolved node B RRC Inactivity Timer.
 10. The method of claim 1 includingrequesting an immediate transition to idle mode.
 11. One or morenon-transitory computer readable media storing instructions to cause aprocessor in a wireless device to perform a sequence comprising: sendinga notification from user equipment of an intent to transition to idlemode; specifying a forced minimum delay for next grant; receiving agrant; checking whether a packet is in uplink or downlink buffers; andif no packets are in the buffers, confirming a transition to idle. 12.The media of claim 11 further storing instructions to perform a sequenceincluding using a medium access control control element to specify saidforced minimum delay for next grant.
 13. The media of claim 11 furtherstoring instructions to perform a sequence including using a logicalchannel identifier for an uplink shared channel in said element.
 14. Themedia of claim 11 further storing instructions to perform a sequenceincluding using a bit to signal a transition to idle.
 15. The media ofclaim 14 further storing instructions to perform a sequence includingusing bits to signal a selectable delay time.
 16. The media of claim 11further storing instructions to perform a sequence including if a packethas arrived in the uplink buffer, transmitting the packet beforetransitioning to idle.
 17. The media of claim 16 further storinginstructions to perform a sequence including if there is an indicationto receive packets in the downlink buffer, discarding the transition toidle.
 18. The media of claim 11 further storing instructions to performa sequence including specifying a forced minimum delay for next grant toindicate when another grant of network access is requested.
 19. Themedia of claim 11 further storing instructions to perform a sequenceincluding specifying a forced minimum delay for next grant that isshorter than an evolved node B dormancy timer.
 20. The media of claim 19further storing instructions to perform a sequence including requestingan immediate transition to idle mode.
 21. An apparatus comprising: atransceiver to send a notification of an intent to transition to idlemode and to receive a grant; and a processor coupled to said transceiverto specify a forced minimum delay for next grant, check for a packet inuplink or downlink buffers, and if no packets are in the buffers,confirm a transition to idle.
 22. The apparatus of claim 21, saidtransceiver to use a medium access control control element to specifysaid forced minimum delay for next grant.
 23. The apparatus of claim 21,said transceiver to use a logical channel identifier for an uplinkshared channel in said element.
 24. The apparatus of claim 23, saidtransceiver to use a bit to signal a transition to idle.
 25. Theapparatus of claim 23, said transceiver to use bits to signal aselectable delay time.
 26. The apparatus of claim 21, including, if apacket has arrived in the uplink buffer, said transceiver to transmitthe packet before transitioning to idle.
 27. The apparatus of claim 26,including, if there is an indication to receive packets in the downlinkbuffer, said processor to discard the transition to idle.
 28. Theapparatus of claim 21, including, said processor to specify a forcedminimum delay for next grant to indicate when another grant of networkaccess is requested.
 29. The apparatus of claim 21, including, saidprocessor to specify a forced minimum delay for next grant that isshorter than an evolved node B dormancy timer.
 30. The apparatus ofclaim 21, including, said processor to request an immediate transitionto idle mode.